Recently, there have been advances in the development of techniques for increasing as much as possible the amount by which the opening in a roof opens in sunroof apparatuses for vehicles. In systems for opening and closing the opening by means of one sunroof panel, there are limits to increasing the size of the opening. Systems for segmenting the sunroof panel have been considered to overcome these limits. However, this is not the best recourse because the configuration becomes complicated if the panel is segmented excessively. With this in view, a technique of a system for longitudinally halving the sunroof panel into a front panel and a rear panel is disclosed in Japanese Utility Model Publication No. 04-26254 (JP-U 04-26254 B).
In the sunroof apparatus disclosed in JP-U 04-26254, a front panel and a rear panel are opened and closed separately by a motor via a wire cable. The operation of the rear panel is in indirect engagement with the operation of the front panel via the wire cable. The motor opens the front and rear panels by pulling the wire cable, and closes the front and rear panels by pushing the wire cable.
More specifically, when in a fully closed state, the front and rear panels are opened in the following procedure. First, the rear end of the front panel is inclined upward (i.e., tilted up). Next, the front panel retracts along the outside surface of the roof, and opens to a half-open position. Next, the rear panel is lowered below the inside surface of the roof. Lastly, while the rear panel retracts along the inside surface of the roof and opens to a fully open position, the front panel retracts along the outside surface of the roof and opens to a fully open position.
As described above, the fully closed rear panel begins to lower at the point when the front panel retracts and comes near the rear panel. Therefore, the timing by which the rear panel retracts is delayed proportionate to the lowering of the rear panel. Since the front panel and rear panel are engaged with each other via the wire cable, the front panel comes into proximity of the rear panel while the rear panel is lowering. Caution must therefore be taken so that the retracted front panel does not come into contact with the rear panel.
One possibility is to accelerate the timing by which the rear panel begins to open. However, if the timing by which the rear panel begins to open is accelerated, the front panel will have not yet reached the fully open position at the point when the rear panel has reached the fully open position. The front panel and rear panel then cannot both be fully opened, and the size of the opening therefore cannot be increased.
In view of this, there is a demand for a technique whereby a roof opening can be opened and closed in a larger amount without the front panel and rear panel interfering with each other.